WO-A-2008/141180 (the content of which is incorporated herein by reference in its entirety) describes a controlled discharge ostomy appliance comprising a pouch having first and second walls, with an inlet aperture in the first wall. A stoma seal is carried by the second wall, and is disposed generally in register with the inlet aperture for sealing against a stoma in use. An outer coupling element is coupled to the first wall and surrounds the inlet aperture. An inner coupling element for supporting the stoma seal, is coupled to the second wall and/or to the stoma seal. The outer coupling member surrounds a periphery of the inner coupling element. The stoma seal may be of an inflatable type, or a foam based type, or a film based type, or an insertable type. Manipulation tabs may be provided associated with the inner and outer coupling elements. The pouch includes a rectangular tail that is distensible from a compact folded-up configuration to a distended configuration when a discharge of effluent into the pouch is desired.
One feature of the above design is the presence of inner and outer coupling elements, that provide control of the position of the seal with respect to the inlet aperture. Although an external seal is contemplated, other illustrated embodiments include a seal that is insertable into the stoma and is, for example, inflated to achieve the desired sealing function.